Insulated conductors or cables which typically include a core with at least one conductor and a polymeric jacket about the core, have been used in varied environments including passage through terrains which include moisture-laden areas, for example, swamps, rivers, lakes and the deep sea. Often, the material of the polymeric jacket permits penetration of the moisture to the core and, eventually, to the conductor which in turn results in deleterious interaction with the conductor. To avoid such deleterious interactions, the polymeric jacket is required to be moisture proofed by means which will remain protective even after the handling of the cable, e.g., after a coiling or uncoiling operation in the loading and unloading of the cable into and from holding barrels or holds in the ship.
Prior art undersea armored cable used by AT&T, which includes a basic deep water cable with a central core and a polymeric insulation jacket, is an example of such a cable. The basic deep water cable is including at least one serving of textile yarn bedding on the jacket, a plurality of coal tar oil-coal tar pitch blend coated galvanized steel armor cables on the textile yarn bedding, a coating of coal tar oil-natural asphalt blend over the armor wires, and at least two servings of textile yarn roving over the coated wires, each roving coated with coal tar oil-natural asphalt blend coating. The "natural asphalt" is an asphalt naturally occurring in asphalt pits in Trinidad. Hereinafter, reference to "natural asphalt" means such a naturally occurring Trinidad asphalt.
In the process of preparing the armored cable, the jacket of the basic deep water cable was covered with at least one serving of the textile yarn bedding. Thereafter a plurality of galvanized steel armor wires were helically wound about the textile yarn bedding on the jacket. Each of the wires was pre-coated with a wire coating "enamel". The enamel coating is a blend of 70-80 weight percent of coal tar oil and 20-30 weight percent of coal tar pitch. The enamel coating was applied to galvanized wires by passing the wire through a vented vat of molten compound. The helically wound precoated (enameled) wires were then coated with molten cable slushing compound. The cable slushing compound specified for AT&T undersea communication cables comprises 35-50, preferably 40, weight percent coal tar oil, the remainder being essentially the natural asphalt. The coated wires were then covered by one serving of textile yarn roving, flooded with the slushing compound, covered with another serving of textile yarn roving and again flooded with the slushing compound. An excess of the slushing compound on the textile rovings was wiped off to reduce the possibility of any sticking (blocking) of coils of the cable each to another.
Cable slushing compound is employed for undersea armored cable systems to provide corrosion protection to the bedded galvanized steel armored wires and provide a moisture-impervious coating on the cable. The slushing compounds have been employed universally for decades in underwater power and communication cables, including the optical fiber communication cables.
Prolonged exposure of operating personnel to coal tar oil-coal tar pitch blend and to coal tar oil-natural asphalt blend without prudent and protective equipment, especially during application of the blends in the molten state, may lead to mild adverse health effects, such as dermatitis and photosensitivity. To reduce the risk possibly afforded by such blends, it is desirable to reduce or eliminate the use of coal tar oil and coal tar pitch in the undersea cable fabrication, while continuing to provide protection to the vital components of the cable against undersea exposure.